Ore-roasting apparatus



(No Model.) 3 Sheets-Sheet 1.

J. R. MOFPITT. ORE ROASTING APPARATUS.

No. 430,741. Patented June 24, 1890.

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(No Model.) 3 Sheets-Sheet 2.

J. R. MOPPITUT.

ORE ROASTING ABPARATW No. 430,741. Patented June 24, 1890.

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A. I B' T my (No Model.) 3 Sheets-Sheet 3.

J. R. MOPFITT.

ORE ROASTING APPARATUS.

No. 430,741. Patented June 24, 1890.

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lNiTnD STATES PATENT Orifice.

JOI-IN R. MOFFITT, OF CHINESE CAMP, CALIFORNIA.

ORE-ROASTING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 430,741, dated June 24,1890. Application tiled January 22, 1889. Serial No. 297.184. (No model.)

To all whom t may concern:

Be it known that I, JOHN R. MOFFITT, a

4citizen of the United States, residing at Chinese Camp, in the county of Tuolumne and State of California, have invented certain new and useful Improvements in Ore-Roasting Apparatus, of which the following is a speciiication.

. My invention relates to apparatus for roasting ores of the precious metals; and it has for its object the treatment of ores by a roasting process at high degree of heat and under pressure of air or in a compressed atmosphere in a close furnace, such operation being specially adapted for working upon what are known as rebellious ores.

To this end my present invention consists in the production of an improved apparatus for the purpose of carrying out this process, having a roasting furnace or chamber to hold the ore, a colnbustion space or chamber inclosing the ore-holding chamber for subjecting the ore therein to direct heat, a means for supplying air under pressure and mainiaining a compressed atmosphere in the roasting-chamber during operation, and valved inlet and discharge openings for introducing the ore and for drawing it off after treatment. In connection with these parts and features there is provided means for treating the air after it has passed through the roastingchamber to extract and recover whatever matter or particles of value may have been taken up by it within the chamber, such means consisting of a discharge-pipe having its outlet end immersed in a tank of water or a solution of suitable substances, all as here- 4inafter fully set forth.

I proceed to attain the end and object of my invention by means of the construction illustrated in the accompanying drawings, in

which Figure l is a side elevation of my improved roasting apparatus for treating ores under pressure and a high degree of heat. Fig. 2 is a vertical section taken longitudinally through the center of the apparatus; Fig. 3 is a cross-section taken through the line :c x, Fig. 2, looking toward the front or discharge end of the roasting-chamber. Fig. 4. is a front elevation of the apparatus. Fig. 5 is a detail view in perspective of the delivery end of the air-pipe in an inverted position. Fig. G is a cross-section at the line :1: y, Fig. 2, looking toward the higher end of the furnace. Fig. 7 is a cross-section at the line jl/ y of the same figure from the front end.

The ore-chamber consists of a cylinder A set out of horizontal, with sufficient inclination from the feeding-in end downward to the discharge end to produce progression of the material being treated, the cylinder being adapted to rotate with a slow continuous movement in one direction. Surrounding this chamber is a stationary cylinder B, of greater length and diameter, similarly inclined and mounted upon an ash pit or box C. This surrounding cylinder is the tirechamber or combustion-chamber, and is of such larger diameter thata clear space is left all around the ore-chamber, which lastmen tioned chamber is entirely open at the lower end to the surrounding cylinder and the heat and products of combustion from the firespace therefore pass through the inner cylin der and come in direct contact with the material. The higher or receiving end of the inner cylinder terminates in a conical neck AX, that extends through the head of the outer cylinder and has the gear W fixed on it outside of the head. A pinion to engage with 'this gear is fixed on a pulleyshaft VTX, that is mounted in suitable bearings W2 in the bracket beneath the gear-wheel for giving motion to the cylinder.

Two sets of rollers D D and E E support the rotating cylinderoutside and inside of the stationary cylinder, of which the rollers D D are set to run on the circular iiange or track AF around the projecting end of the ore-cylinder, and the others E E are similarly set to take a flange Ginside at the point where the neck AX, and the cylinder proper are joined together. That portion of the surrounding combustion-space in which the rollers E E and t-he iiange G and also the conical neck are situated is separated from the tire-space around them by a partition formed of the fixed flange l-I and the removable ring l, that together form a tight partition between the two cylinders, suitable packing 7o being placed between the two parts l-I and I and between the ring I and the ore-cylinder. The space beyond the head of the ore-cylinder in IOO which rotates the neck is thus eut off from the iire and no escape of air or products of combustion can take place from the main chamber. If the joints are well packedfat this point, the opening through the head of the stationary cylinder need not be packed. The material to be treated is fed into this end of the cylinder from a hopper L above thelevel of the receiving end by means of a spout or close conductor M, terminating' in a curved end that extends into the opening provided for it in the projecting end of the neck. This conductor can be a pipe ot' any suitable length to bring the material from a supply-hopper at a distance, and in the treatment of some kinds of ores where it may be of advantage to subject the material to gradually-increasing degrees of heat, instead of dropping it directly into the cylinder from the hopper, the pipe M can be made longer than is represented in the drawings, and the hopper can be set at some considerable distance from the furnace, but at suitable elevation to secure proper fall for the material. If found necessary, a screw conveyor could be placed in the pipe to feed the material forward and prevent choking; but such devices are already in use, and are too well known to require either description or illustration.

The feed-pipe M is furnished with two sliding valves N N X, that are arranged in the upright portion of the pipe at suitable distance apart to feed in the ore in charges or portions without escape of air or gases from the furnace. By means ot' hand-levers u n these valves are worked alternately, so that the pipe and outlet. fromv the ore-cylinder is always practically closed to the atmosphere.

The lower valve is closed in feeding before the upper one is opened to let in a charge from the hopper, and then the top valve is closed before the bottom one is opened, and this is repeated as many times as necessary to charge the cylinder.

The surrounding lire-chamber, in which is thus mounted the ore-cylindr-n, can be either cylindrical to conform to the shape of the inclosed cylinder, or it can be made rectangular in cross-section. Itis mounted directly on the close box C, and has in its bottom side, near the lower end, a grate-surface P, formed ot' a perforated plate. This part l? tits au lopening in the shell of the cylinder and is detachable, so that it can be removed for cleaning or repairs. Access to the interior of the cylinder is had through the door BX, that closes the lower end of the outer chamber,

and through this opening' the .grate-surface.,

can be reached and taken out. There are also provided openings B2 in the sides of the outer chamber for introducing' fuel, which are tightly closed by doors C', and the box C below, that forms the ash-pit, has similar openings closed by doors.A The joints at all these openings should be wellpacked to coniine the air and products within the two cylinders, as the working-pressure therein is kept above that of the atmosphere outside. This condition within the cylinder is maintained, andthe air is supplied to it by means of a suitable blower or pump and an air-receiver or tank, from which a pipe is carried into the inner cylinder, and a supply is also furnished for use under the grate-surface.

In the present construction l have placed the air-receiver S directly beneath the furnace in the bed or foundation as being a simple and compact arrangement that allows direct connection with the ash-pit and the orechamber; but the receiver may also be a separate structure, placed, if desired, at a distance from the furnace, with an air-pump connected to it. The air-pipe T, leading' out from this receiver, is carried through the top of the outer chamber and down into it in front of the open end of the ore-cylinder, where it is turned laterally and carried toward one side a short distance, from which point it is again bent at a right angle to extend in a longitudinal direction into the ore-cylinder and close to one side of it. This extension of the pipe is a section or piece of semi-cylindrical shape in cross-section, with the flat side turned downward and perforated with numerous small holes, as seen in the detail view, Fig. 5, and the inner end is closed. TX is this part, and t t are the inlet-apertures for the air. Its position is close to the side of the cylinder, with the perforations facing the body of oro lying against that partof the cylinder which is directly underneath and nearest to the pipe, so that the air is directed in fine jets against the ore, the direction of rotation of the cylinder being toward the pipe from the bottom. By this arrangement the ore is carried toward thel air-jets by the rotation ofthe cylinder.

The air-receiving tank is connected with a suitable pump or blower by the pipe SX, and the pipe leading from the tank into the roasting-cylinder is furnished with a valveT4 for controlling the supply or shutting off the air.

The outlet for the air and gases is placed at the opposite end of the ore-cylinder in the back ot' the ore-feeding spout, so that all this matter is caused to pass through the fresh ore contained in the pipe or in progress through it toward the cylinder, where along feed-pipe is employed. Freni this outletU the gaseous matter and products from the ore and fuel within the cylinder are carried by a pipe V, that dips at the lower end into a tank of liquid, by which the pipe is sealed and the desired pressure is kept in the roasting-chamber. This pressure can be varied in degree by raising or lowering the end of the pipe V in the liquid-tank V2, and for this purpose the upright portion of the pipe is connected at 'UX to the section of pipe that is fixed in the outlet by a flexible or swinging joint, so that the end of the pipe can be raised or depressed in the liquid. By this means I obtain two results, of which the iirst consists in retarding the discharge of air and gases sufficiently to maintain the desired degree of pressure in the roasting-chamber, and at the same time allow a continuous discharge to take place during the operation, and the second consists in taking out and recovering from the air and gases, by passing them through water or a suitable liquid solution, such valuable particles and matter as may be taken up and carried out of the roasting-chamber. The liquid used for this purpose can be a saline solution, or any of the well-known solutions of salt and alum, or a solution containing or composed of acids of such character as may be found adapted to the purpose. The outlet for the roasted ore is kept closed to the atmosphere by a valve so arranged that the ore can be drawn oft' during the operation. In the present construction the open end of the ore-cyl inder sets over the trough or chute Y, that leads out from the bottom of the stationary chamber and through a casing YX, in which is set a rotary valve Z, having pockets ZX. rlhe valve is mounted for rotation upon a horizontal axis Z2, and is operated with a slow motion by a belt and pulley or other suitable device for moving it from some part of the machinery employed to tn rn the ore-cylinder. The lower part of the casing fits closely over the curved top of the valve, sufficient width ot' face to form a tight joint being obtained by flanges, as shown in Fig. 2, and these parts, working against each other, are kept lubricated and cool by mounting the valve within a tank R, holding water. rlhe valve is thus partially immersed and always turning in water, and the tank also forms a receptacle for the roasted ore, which can be taken out by any suitable device-such as an endless chain of buckets, for instance, as I have shown in Fig. 4t of the drawings.

As thus constructed for operation, it will be seen that the heat and products from the fuel are carried through the ore-holdin g cylinder, and are therefore brought into direct contact with the material being treated. The air from the receiveris constantly supplied to the ore-cylinder to maintain a compressed atmosphere therein during the operation, and is caused during its discharge to pass through a body ot' liquid. Air for combustion is also introduced below the grate-surface from the air-receiver by providing an inlet-opening in the ash-pit, litted with a valve Q, Figs. 2 and (i, for regulating the quantity as well as the times of supply. At the beginning of operations the tire is startedin the combu stion-ch amber and airintroduced under the grate-surface until the whole interior space is brought to a highheat. The openings are then closed, and

the ore is fed in by opening and closing the valves in the feed-pipe. Motion is then given to the cylinder at slow speed and the air from the receiver is let in through the air-pipe T. In the case of some kinds of ore containing too small proportion of combustible matter in itself, I iind it of advantage to introduce some fuel material to accelerate or assist the process-such, for instance, as charcoal or sawdust-which can be fed in through the orefeeding pipe as required from time to time with the ore.

The form of apparatus which I have represented in the accompanying drawings will be found well adapted to the treatment orn such ores as are difficult to work by the ordinary roasting processes, and by its use a considerable portion, if not all, the valuable particles and matter heretofore lost in these roasting operations can be saved.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is-

l. In an ore-roasting apparatus, the combination of a close combustion-chamber, a roasting-chamber mounted therein for rotation, having one end open to the surrounding chamber and an ore-feeding inlet in the opposite end, which is controlled by a valve for introducing the ore and preventing at the same time escape of the internal atmosphere of the chamber, a discharge-opening at the opposite end of the chamber, also governedby a valve to discharge the roasted ore, an airpipe connected with a receiver, in which is contained air at a pressure suiiicient to maintain a compressed atmosphere within the roasting-chamber, and having its termination inside the inner chamber to deliver the air in close relation to the ore therein, and an out let-pipe from said chamber, adapted to deliver the air and gases from the chamber into a body of liquid, substantially as described.

2. In combination with an ore-roasting furnace consisting of a stationary combustionchamber and a close ore-cylinder therein mounted for rotatioi'l, as described, and having connection with a tank or receiver holding air under pressure, a grate-surface, and a closed ash-pit beneath it, having connection with said air-supply by an independent. pipe or inlet-aperture, as described.

In testimony that I claim the foregoing I have hereunto set my hand and seal.

JOHN R. MOFFITT.

Witnesses:

CHAs. D. NVHEAT, C. XV. M. SMITH.

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